The present invention relates to a method of searching alphanumeric data stored in electronic form and to apparatus for implementing this method. The invention is applicable in particular, though not necessarily, to mobile communication devices which store a directory of names and respective telephone numbers.
Conventional mobile telephones have electronic digital memories in which can be stored directories of names and respective telephone numbers. It is not uncommon for these memories to be able to store several hundred individual entries in which case searching through the stored directory can be a complex operation. For telephones with extensive keypads, two search options are generally provided. The first option involves the use of xe2x80x98upxe2x80x99 and xe2x80x98downxe2x80x99 switches to scroll through the directory in alphabetical order, one entry at a time, with the currently selected entry (either name or number) being displayed on a display of the telephone. The second search option is to enter a search key (or search key variable) consisting of the first character, or a number of initial characters, of a name to be searched for, and to commence the search operation by pressing an xe2x80x98enter switchxe2x80x99. The first name in the directory that matches the search key is displayed on the display. If this name is not the one that the user requires, then previous or subsequent entries can be selected by use of the up and down switches.
There is however an ongoing desire to miniaturise mobile telephones and other mobile communication devices and one way in which this is being achieved is by reducing the number of user switches; in particular, alphanumeric character entry switches are being removed. This of course makes conventional fast searching by directly entering the first letter or first few letters of a name impossible. Several xe2x80x98reduced switchxe2x80x99 search methods have been proposed to overcome this problem. For example, WO93/14589 discloses a mobile telephone in the form of a pen in which a cap of the pen is rotatable in a xe2x80x98name directory display modexe2x80x99 to enable the user to scroll through a stored directory. Slow rotation of the cap causes the directory to be scrolled through one entry at time whilst rapid rotation of the cap causes the directory to be scrolled in steps of a fixed interval, e.g. five names at a time. WO93/14589 also considers stepping between the first name entries beginning with each different letter of the alphabet, i.e. from the first entry beginning with xe2x80x98Axe2x80x99 to the first entry beginning with xe2x80x98Bxe2x80x99 and so on, in response to rapid rotation of the cap.
It is an object of the present invention to provide an improved method of searching a stored directory of alphanumeric entries using a reduced number of search switches.
According to a first aspect of the present invention there is provided a method of selecting an entry from a directory of alphanumeric entries stored in electronic form in the memory of an electronic device having a display and at least one user actuatable search switch, the method comprising the steps of:
(1) displaying one of said entries on the display and defining as a search key the first character of that entry;
(2) using said search switch to extend the search key to include one or more subsequent characters of the displayed entry, where the number of characters making up the extended search key is n; and
(3) searching the directory of entries in alphabetical order to identify a first subsequent entry not commencing with the extended search key, and displaying the identified entry if one exists.
Preferably, the search key is extended by one character each time the search switch is actuated, whilst the electronic device is operated in an xe2x80x98extended key modexe2x80x99. The method may comprise the step of responding to actuation of a second search switch to shorten the extended search key by removing one or more of said subsequent characters from the key. Again, the extended search key may be shortened by one character each time the second search switch is actuated, whilst the electronic device is operated in the xe2x80x98extended key modexe2x80x99.
Preferably, following the search, the search key is redefined as the first character or characters of the identified entry, sufficient to distinguish the search key by one character from the beginning of the previously displayed name. Optionally, steps (2) and (3) may be repeated based upon the new search key and the newly displayed entry.
Preferably, said searching of the directory of entries using the search key may be commenced following actuation of the first mentioned search switch for a period of time greater than a predetermined initial time period. More preferably, following the elapse of each further predetermined time period after the initial period, step (3) is repeated using the new extended search key as defined in the preceding paragraph. In one embodiment of the present invention, in response to actuation and subsequent deactuation of the search switch before elapse of the initial time period, the searching step comprises first determining if the next entry in alphabetical order commences with the extended search key. If yes, then the search is stopped and the currently displayed entry continues to be displayed. If no, then that next entry becomes said identified entry and is displayed. The search key is defined by the first character or characters of the identified entry, sufficient to distinguish the search key by one character from the beginning of the previously displayed name.
In another embodiment of the invention, the method is responsive to actuation of a xe2x80x98Down-Scrollxe2x80x99 switch to replace the currently displayed entry with the next entry in alphabetical order. In particular, the method may be so responsive following actuation of the Down-Scroll switch for a time period less than some predetermined time period. The method may respond to actuation of the Down-Scroll switch for a time period greater than that predetermined time period by displaying in alphabetical order the first entry stored for each letter of the alphabet. The method may respond to actuation of an xe2x80x98Up-Scrollxe2x80x99 switch by similarly stepping through the directory and displaying selected entries, but in reverse alphabetical order.
Preferably, the method comprises restricting the search in step 3) to those entries which differ from the Search Key only by the final character of the Search Key. More preferably, the search continues cyclically for the entries searched, i.e. after display of the final entry, the first entry containing the Search Key is again displayed and the search repeated.
According to a second aspect of the present invention there is provided apparatus having an electronic memory for storing a directory of alphanumeric entries, the apparatus further comprising;
a display;
at least one user actuatable search switch; and
signal processing means coupled to said user actuatable switch, for detecting actuation thereof, and to said display, the signal processing means being arranged to display one of said entries on the display and to define as a search key the first character of that entry, to respond to actuation of the search switch by extending the search key to include one or more subsequent characters of the displayed entry, to search the directory of entries in alphabetical order to identify a first subsequent entry not commencing with the extended search key, and to display the identified entry if one exists.
According to a third aspect of the present invention there is provided a mobile communications device comprising:
a display;
at least one user actuatable search switch; and
signal processing means coupled to said user actuatable switch, for detecting actuation thereof, and to said display, the signal processing means being arranged to display one of said entries on the display and to define as a search key the first character of that entry, to respond to actuation of the search switch by extending the search key to include one or more subsequent characters of the displayed entry, to search the directory of entries in alphabetical order to identify a first subsequent entry not commencing with the extended search key, and to display the identified entry if one exists.
Whilst the present invention is particularly applicable to mobile telephones it will be appreciated that the invention is applicable to all electronic devices in which alphanumeric entries are stored and in which it is desirable to be able to conduct rapid searches of the stored data using only a very few user actuatable switches. These devices include personal organisers (or personal data assistants-PDAs) and combined mobile phone and PDA devices.